It is well-known to collect, store, and administer blood from a flexible bag. The Walter U.S. Pat. No. Re. 25,129 discloses such a system in which a blood bag port has a short tube segment with an integral diaphragm 16a (FIG. 3) which is punctured to gain entrance into the bag. The short tube segment has its sterility protected by a pair of opposed peal apart tabs. The tube segment of this patent is made of a thermoplastic material with an integral thermoplastic diaphragm extending across its passage. Such construction is fine for blood bags in that usually a port system is entered only once to either select blood in the bag or dispense it. Thus, a thermoplastic diaphragm need not be "resealable" after removal of the puncture spike.
With flexible bags that are used to dispense intravenous solutions, such as saline, dextrose, etc., it is sometimes required to periodically inject into the bag additive medication either prior to or during the administration of such solution to the patient. Since there are repeated injections through an additive port, it is necessary that the additive port reseal after removal of the injecting device, which often is a hypodermic syringe. U.S. Patents such as U.S. Pat. Nos. 2,838,046 and 3,064,652 have proposed the use of a puncturable, resealable rubber plug secured to the wall of a medical liquid bag. Both of these patents have used a flanged support to seal the rubber plug directly to the face surface of the medical liquid bag. This construction has a disadvantage in that the rubber plug had to be sealed to flat sheet material that was then subsequently folded and sealed on three sides to form a bag. The folded edge is shown as 17 in U.S. Pat. No. 2,838,046 and at numeral 3 in U.S. Pat. No. 3,064,652.
New Zealand Pat. No. 180,949 describes a medical liquid bag currently being marketed in New Zealand where it is commonly known as the Dutch Red Cross (DRG) blood bag. The bag described in this New Zealand patent has a thin walled, flexible tube with an integral thermoplastic diaphragm 32 against which fits a puncturable, resealable plug 34. A substantially more rigid section 47 urges the plug against diaphragm 32, which is not resealable. The actual manufactured DRG bag sold in New Zealand, item 47 which holds in the plug 34, is an extruded segment of tubing sealed within a tube 22, across which is formed integral diaphragm 32. The entire puncture port system is then sealed between two opposed walls of the bag, such as shown in FIG. 4. A portion of the sealed bag walls is ripped apart to remove a tab section formed of the bag walls directly above the puncture port. This tear line extends across approximately one half the width of the DRG bag.
Such bag construction, such as shown in FIG. 6 of this New Zealand patent, can cause problems in forming a reliable, leak proof seal between the tubular element and the two opposed bag walls. This is because the thin, flexible lower portion of the puncture port absorbs a different amount of heat than the stiffer, more rigidified section at the upper portion of the port during sealing procedure. Also, sometimes it is difficult to get a proper seal between a very thin wall section of the bag and the tubular segment located between the bag walls that has a substantially greater wall thickness. Once the wide tabs have been torn off to expose the puncture port of the New Zealand bag, it is extremely critical that the seal along edges of the tubular puncture system remain intact, and no liquid seepage can exit the bag at the seal between the bag wall and the puncture port system.